I'd like to replace an old receptacle/switch combination with a new GFCI/switch combination. The old outlet was always hot, and the switch controlled power to a second (outdoor) receptacle. I need that outdoor receptacle to be protected by the new GFCI.

There are only three wires in the gang box:

  1. Black wire - was connected to the old Outlet/Switch on a screw labeled "Common".
  2. Red wire - connected on the opposite side of the black wire, on the top (switch) half.
  3. White wire - connected on the opposite side of the black wire, on the bottom (outlet) half.

With only these three wires, can I replace this old receptacle/switch combination with a "Leviton GFSW1-W Self-Test SmartlockPro Slim GFCI Combination Switch Tamper-Resistant Receptacle"?

If yes, how would it be wired?

  • Can you post photos of the inside of the box in question please? Nov 10, 2020 at 4:17
  • It sounds like the old switch was part of a 3-way setup. Is there another switch somewhere that also controls the outdoor receptacle?
    – FreeMan
    Nov 10, 2020 at 11:46

1 Answer 1


Given the wire topology you have there, it ain't gonna happen.

There is no way to protect another recep with only 3 wires coming into the box. You need a minimum of 4: unprotected supply Hot and Neutral, and protected-zone Hot and Neutral.

You can install that GFCI+recep+switch combo, but you won't be able to use the LOAD terminals for anything, and the only socket that will be protected will be the one right there.

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